Process for strengthening steel, cast-iron, and alloy castings.



HERBERT EDWIN FIELD AND FRED CLINTON TILTON DANIELS, 0F WHEELING, WEST VIRGINIA.

PROCESS FOR- STRENGTHENING STEEL, CAST-IRON, AND ALLOY CASTINGS.

LMMALSF.

No Drawing.

To all whom it may concern:

Be it known that we, HERBERT E. FIELD and FRED C. T. DANIELS, citizens of the United States, residing at Wheeling, in the county of Ohio and State of West Virginia, have invented certain new and. useful llmprovements in Processes for Strengthening Steel, Cast-Iron, and Alloy Castings, of which the following is a specification.

Our invention relates to improvements in process for aging cast-iron and alloy cast: ings.

The object of our invention is to provide a process for treating castings so that they will be greatly strengthened without decreasing their hardness and wear resisting qualities.

Another object of the process is to provide a simple and inexpensive process in which the castings are treated to accomplish the before mentioned results.

Steel, iron and alloys have been treated by heat from the time of their first manufacture, such as being annealed, hardened and tempered, but our particular process is different from this in the fact that we do not either anneal, harden or temper the castings as is commonly understood and carried out in the trade.

It has long been known among the iron 7 manufacturers that iron, steel and alloy castings strengthen themselves by aging for a number of months or even years, and it is the object ofthis process to accomplish the result of aging in a short length of time at' a very small cost.

An ironor alloy casting is taken as soon as it is cast and cooled down to atmospheric temperature and is treated with our process for aging, or it may be taken before it is cooled to atmospheric temperature. The casting is preferably cleaned from the adhering sand,and the sink-heads, etc., are preferably removed before the casting is subjected to our process. The casting thus cleaned is packed and put with an inert material in the container, which packing material is preferably the old used foundry sand sifted to remove the metallic iron, scale, etc., therefrom. The container is thus placed in a furnace preferablyusing natural gas and it is gradually heated up to 1250 degrees Fahrenheit. The casting is maintained at this temperature for a time proportionately with the size thereof and then allowed to Specification of Letters Patent.

Patented Dec. Mt, T015.

Application filed October 7, 1914. Serial No. 865,510.

cool. When the heat of the furnace has reached 1250 degrees Fahrenheit, it is maintained at'this temperature for a period of time as is long enough to bring about this aging or maturing of the casting. This takes from one to seventy-two hours dependng on the size and condition of the casting. Seventy-two hours is long enough to bring about this process although a longer time could be'employed with no harm and little extra benefit. Maintaining of the heat at 1250 degrees Fahrenheit for less than five hours would strengthen the casting, but not to the extent where it is left for a long period depending upon the size of thecastmg. The flame 1n the furnace is then grad- -ually decreased until the temperature has fallen to about 850 degrees Fahrenheit when the flame is shut ofi entirely and the dampers closed and the furnace allowed to gradually cool off by itself. When the furnace has cooled to about 500 to 300 degrees Fahrenheit, the casting may be-removed from the furnace and the casting and container allowed to cool down to atmospheric temperature more rapidly.

In iron and alloy castings the outside sets very much faster than the inside and consequently occupies less space than does the inside. This consequently causes the outside to stretch over the inside of the casting during further cooling, causing numerous strains which makes the casting brittle and liable to break under the shock. Our improved process in the heating thereof relieves the casting of the strains due to the rapid cooling of the outside of the casting in its manufacture and thus produces an improved casting.

While we have described in the process that the casting is heated to 1250 degrees Fahrenheit, it will be understood that if the heating would not go beyond say 850 degrees Fahrenheit the strains would be partly re moved. The castings could also be heated to 1350 degrees Fahrenheit without destroying the chill surface.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. A process for strengthening castings consisting in heating the castings to 1250 degrees Fahrenheit, maintaining it at this temperature for a period of time, allowing it to be gradually cooled to 850 degrees Fahrenheit, and then allowing it to cool more rapidly to atmospheric temperature.

2. A process for strengthening castings consisting in placing the casting in a furnace and heating it to a temperature of 1250 degrees Fahrenheit, maintaining the casting at this temperature for a period of five to seventy-two hours, then allowing it to gradually cool in the furnace to a temperature of 850 degrees Fahrenheit, and then shutting off the heat supply and closing up the furnace and allowing it to gradually cool to atmospheric temperature.

3. A process for strengthening castings consisting in packing the casting with an inert material in containers placing the container in a furnace and heating it to 1250 degrees Fahrenheit for a period of five'to sevent -two hours, then reducing the heat in the furnace and allowing the casting to cool to 850 degrees Fahrenhelt, then shutting off the heat from the furnace and closing it up and allowing it to gradually cool to atmospheric temperature.

4. A process for strengthening castings,

consisting in placing the casting in a furnace and heatin it to 1250 Fahrenheit for a period of 5 to 2 hours, then gradually reducing the heat in the furnace and allowing it to cool to 850 Fahrenheit, then shutting off the heat from the furnace and closing it up and allowing it to more rapidly cool to atmospheric temperature.

5. A process for strengthening castings, consisting in placing the casting in a furnace and heatin it to 1250 Fahrenheit for a period of 5 to 2 hours, then gradually reducing the heat in the furnace and allowing the casting to cool to 850 Fahrenheit, and then shuttlng off the heat from'the furnace and allowing it to more rapidly cool to an atmospheric temperature.

In testimony whereof we hereunto afiix our signatures in the presence of two witnesses.

HERBERT EDWIN FIELD. FRED CLINTON TIL'ION DANIELS- Witnesses:

A A. P. AYLING,

R. R. S. CRAWFORD.. 

